'The end of the human race'. On the list of doomsday scenarios that could wipe out the human race, super-smart killer robots rate pretty high in the public consciousness.
All stars live by fusing hydrogen into helium. In the first step of the process, two hydrogen atoms fuse to form deuterium. In the next step, another hydrogen atom fuses with the deuterium, creating a rare isotope of helium that has two protons and one neutron in its nucleus. In the third step, two of the rare helium atoms fuse to create a single normal helium atom and two hydrogen atoms. The fusion pathway described above requires six hydrogen atoms to create one helium atomâhowever, there are two hydrogen atoms left over at the end of the process. The net result is that it takes four hydrogen atoms to make one helium atom.
Proton-Proton Fusion. This is the nuclear fusion process which fuels the Sun and other stars which have core temperatures less than 15 million Kelvin. A reaction cycle yields about 25 MeV of energy.he second step of the proton-proton cycle. This step involves the weak interaction because it involves the transmutation of one of the protons to a neutron in order to form deuterium. This process requires energy and produces a positron and an electron neutrino.